SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1607fd8dfb004059123e102c0feba6f7aef91267c9842b429ec2b1cbe69d590d' 
  AND token = 'P+GxyDEtQX3XhlgPYGq1x9hrHKQGmrvwBXaE1sPETjw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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