SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '031759e30094fc2a85b949e6c91319a06d2dc49a1c6f6c9fc9572b4d1d7cdc15' 
  AND token = 'CJ4G2EN1ceQtk2OF9oPzmLx30gsoGgSN54tbvPvbMlg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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