SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '6514a4ecf534be5c202decc25f0db71b581268bc4231cd8c8ff28b3a0d1fe985' 
  AND token = 'd2mi0RYKVAAw4hL2IO+73s3RgG+zC9hrYZv4Rxx71WY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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