SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f45f671a44c4ec1e2e9c70260d6f01661d327c5ca2344cf2c555ac469850139' 
  AND token = 'ZRPVIukUVWfFStNRVIt4CgkRiNVMO+Jlvl02sfdKsu4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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