SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c40c2602f43249c3827ebfd47851c2e833a854c765c601882b650ec48bba84e3' 
  AND token = 'IsfYtpjmTJjLj/fkRZdWtBneuc0X6V+XnIhb94t3ClY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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