SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7e18985ff504d896a1157b7e1e11e7b13f8b16c2f0321af2651824fadbf0847' 
  AND token = 'CJIaUr4QgaXvVHTV9rx3V0Z6enwM5T0La07TIXyOIRQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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