SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9a742026086b0d37fe4d14bb73330671253b0d9b0643364bd0540409c83e1f8' 
  AND token = 'otieGGcyegOYiRsEKHgxPF6JRyNbIRKngGLXFTcFQy0=' 
  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"
    }
  }
}