SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '744db781f82f08e46179850ca37bc1447973d2cfdabfb2512c68ff2c0ded133e' 
  AND token = 'e3gNyM/rTzRR+hk20/8BKpdvQys43wOLxudQVhKiS0c=' 
  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"
    }
  }
}