SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb1ebb72a5e02338f56bf061e3bb6b1d2d95c2870b6bab279d48bd3266d72f18' 
  AND token = 'I2fjAVYkmKFw16HGeko9DgAgZykDsfQwqNnrGYuUMk4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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