SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '954e5bf24989906d01f638419b6eda4f4a81af4884a79ee1db793db6e0edd3ab' 
  AND token = 'plG5B/2FaoqNEtpqw7Oee6nZSEXntxmmrZVMoC4Vulw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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