SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4003d2f95dfdd97b03aca00dba261f5f3fa09f5716fc1e024907b9a67b8ae7b4' 
  AND token = 'AwhgT+yiGKfl1Nh7QBZUmlqsYiY1tyf3JnwdHUIDCUc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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