SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c14604f7640f97985eda57ce0be2d5757f770a93610bc277444092096f5da8e2' 
  AND token = 'ISERi3AA3kykMNtCGrw56v26jtg4Lb2ptocgwFCLsoM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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