SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4b2a77844118dda668684acb5c285046573f672b86f9958a2f05897c4db802f' 
  AND token = 'UvicxozNORClOFxBRhsNR5CYDHTW60mmC468wuB9kTM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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