SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5992606354cf3c4af3e1bd5c3e877532f93d77c4adda635581c3055259100290' 
  AND token = 'Sdvjh/oe0wDy1R070a8efTLUFHPSKDVPdn2zdGc4aPM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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