SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '38c450fa7389886e516c677780b9dec3f2c9bc3e6d8cfba339b8335080b1a6c0' 
  AND token = 'a/2YBcNAhRJZz2jRGKOCCvQMyGbq16Xpi5/B+b4XolE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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