SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c78a71f2b88b71635cc436783dc0ea85bae0058a3d2c3f0b943369be97935b5' 
  AND token = 'OaTW9w78Q7Dn9yHz6IXmnPc9sFJkhuficJ09gg1DP+E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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