SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '5a5c305379f539804eeb1ebeedc9add3d8046808b56a805d22de5845edacb598' 
  AND token = 'BxTwJuHBeKEEzOEPmOHLglOneVOZq7Quf9p1qwubcDo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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