SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd679fd0b1e74c52a1868c9b887e771b7a942d3993d4296fa84f9172c54c063a0' 
  AND token = 'qYcRc/wnx1j0GHeDVs7txZ2alVshIe4MlV3fMPvtZQw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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