SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a80734a352db0f32b6564037bd3df6cf4d0267048623070774fcd15f84ccd4ff' 
  AND token = 'yxvXe8cQrrKRECfKptTzqRHH6HXbCgv5/LVkNMx3/DY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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