SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c9123c082e7b7418791b103978711de23133af679a0aaee1d051d7d67d685b25' 
  AND token = 'sFZZp+onDvmtG2yJkBGyr8HjhAjMRNUgoLnKMbf6kTI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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