SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f92fc8f860979be40c235cd443b1ab3562316219b36b4c597b8ece2c394f8243' 
  AND token = 'UPSNoC1u7v+1/u2YdanpWTBVaBcpjUI1bVHu5fsuIgI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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