SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18c52cd2e1db633589b396f821c651c3b5d8e1ac0cf0daffa56a5110f63ae15d' 
  AND token = 'viv5AN2agPpa0PdVwTc843/V7f10KmVzYiMuOStKeB8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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