SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef8a6e782234813275f9e28c445e3f2c776675b62b98503a58ab19d0fe1c49d0' 
  AND token = 'QKFGfRZmo8z+6V1pn+OaCc7BfYRZFJnSu4TVecZw36g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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