SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97057c367aae283f2bfa80d2f7185901a340ced489e50964a4184391b90f5866' 
  AND token = '9Lf8ZdsVC3qscOwzZVvHYa5s3B17B8OnUeJwWQULmvk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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