SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20c2aba39f04edac08787145532ad23cac7ebd561ac7090667fe14c39d85586c' 
  AND token = 'w6wSVjyiA9bzpUFYZiVmssugMv2qtRsaXZcV9C9JA4I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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