SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '184d63d78109ff89604c42c574257506d15e87f311c16f3beee4966bb919a51a' 
  AND token = 'crML8Ojxsv975N3koa20o+JzjFnECIYO4lcSqQdbAdQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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