SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2535d7d8b3d2e2ea8aefd641094903c2b32a1047883ed6ea21b9ab35822aa1f' 
  AND token = 'GtGqnJLknuHoZ45pFhqXyZ8LTx/3geaPe5z4WQfABlc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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