SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '989f7ae1266f812f24d25f50e82c0db916f99fac83007fedb465f5c678067992' 
  AND token = 'iwqN4nt/rzk95GzTugCx0WNWyRSuuY+WYKJrmhDFcxU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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