SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9fb76ea97eaee616124a0c68a97a402ee10dee921d0573c18f222f4532104fd' 
  AND token = 'mQKjr8ubadSqisRLpfmPL9Cfy2x1JnWxUGWu5h/P/vo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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