SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f30bd918fcaa503d36b2cf57a3432f106a57507b97ece6c20f339d7ddbe284a9' 
  AND token = 'i6LjqMQW/LEjqPB5hOGuJr6Qn/3IcKhYB8Qx2PLsl4Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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