SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0e8e9ec5807e9522d22254999a0a585a8f8e7fe4b6fd1c889c338348de36187a' 
  AND token = 'Qs3bST/C3dzA4ezHtt67eJ6aaOrZA/qwPECGTWN3kdM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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