SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'bcd6c604bba3af9ab520c09b8c06d2b69104a5556a717e675091ac22c308e68a' 
  AND token = '4oV+H+XRyxzmY2o5kPOJ3ZRiCS9y372wEEmGakKcPng=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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