SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3dad7326cc92e7f02553d33e2887e74697ce16ea35d33d395e32330f4e67f3fb' 
  AND token = 'tU6haCGuPvns1u4Je81BcvDPSiOKl28lTJXCumuAiHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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