SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c253ada94b67f2178deb2fb03c7944574d41cf2db41eb445e3735ab44187b645' 
  AND token = 'dBSxOb9zaAHj81cMWl4MS431/8t0BZ4BA9wBgtoBYVI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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