SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7e1cd4cf74f019e8b73dfaf6ffb90fe1033d8839d772136e8230856104d64f9' 
  AND token = 'Kvlq/CqjHCUhuC0N1mzb5BtN2RdbbHXKr6wqwjCKu5U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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