SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56abfc00d7409afa714b9f14033e3f5745ceeff5397e122e06fce439b57abb9f' 
  AND token = '45DXYSp+rSyzmUqODKtc29FxVrmtLerFDXo2UwPBCl0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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