SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '24c80776f7600123a27a76fe3b422130c46f749742bc35e344a00d96a20bc24f' 
  AND token = 'x3dB0zq5v5Ubm5lth2u++0pKgaLCJYujusPgeJVhouQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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