SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50c5ebb38e96b63b8d21d7fbfebb37db8f40afda1aac6085172fed63052570b2' 
  AND token = 'FWK4ozzxM5j04rLXznj4CUegtfL8ppZi2pqncJUjAWY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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