SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e0218bf6ee5b6d583875dd4d475b41faacd3bde732219bc176320a26afa5297' 
  AND token = 'bPPKjDjrRKrlEtFKKnScG4AGhvON1CKLXVKLpaOPEZ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}