SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '54dae82cd7b4b781c643cd6cde116634047df609b70e8f084b71fd88ac19d1a6' 
  AND token = '/DJwFnJwFrrBiBSrcFADPGgzpVWTZ3DwN/Xv/mADIAU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}