SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2d8c7c4ae198fc41c1effa89773660a0a9f315b738ba6f2d9daec4c67d4e522d' 
  AND token = '/tmJ6PjWYB7gz4fGo8101h5PbPoCqcGdXiOyDaIJ7VI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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