SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0c676c348f67ba8e497a0b2d707a256fefe698e8f65fe92dd2ebec754abe9df3' 
  AND token = 'xtxefYQOXITDIK8qi7KW/EeDR5fDahthz8yLAAU8CQM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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