SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37eabc2daedce8bb5093446516670a639a008ecddf8778ff7d231c52611ea137' 
  AND token = 'N9p1yEXdpzBcPPZXHY/huOeSmGsG20DkQaCBLwjP4xg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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