SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f9a507dd9b56dfbb46d2f8f2442129dfefcfe5f5d0b2550efb80eb6001b4626' 
  AND token = 'FnxUBnRQJT6QXI1IL3YXTkXICPwRjf6GYJnEuBwV3PU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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