SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af8177344190215b561a6a4f321118a171165cc9a3db1589fd7f74a2e5658b4b' 
  AND token = 'aw87gawWaTUTXXtvsnRIMQGExdPvH3Cg1+WTM2XRAaE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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