SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6cb38ab2f1c8070b23bbf9442c82b7a15f41eb35a7d5d3cd320aa4a8415e11c' 
  AND token = 'AgdLd9xbvHc3G7SjOV7V4LFNJPPtBh8bfn2L0FzjOVw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00121

JSON explain

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