SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0ac39afb8340eb34b97c28076f8cbcc8d1ff2d19480de5862a187162a97630e' 
  AND token = '6pT9OQmCATzu5gPyuqsoLFXUS5Pym4cF/iGKa3A5vBQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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