SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bd517f40c32ee4a373fc297e4bc164f19803de4315f39c09449670c6e5661c37' 
  AND token = 'AaNYsF7PMzQHCcjPpknHzZCspwCJrTQTmHbAeG6i00k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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