SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c74938dc99a86cad4c4cf9b1a37e9499090b9123b26fc5bf61708aea76a37e2' 
  AND token = 'JzkuvTmMRGrQhZo9jba9ATGhNka/rmowRnUsIanI9ZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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