SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e2a26c387b186a834f6208cf4c466a8b1a9a8c11f0fc2f2176cc9c334a234537' 
  AND token = 'YyUUl/hjgPNAc4r4eTBY4a/b6SlnD/3srxovjsXknUc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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