SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '7f02969f8f0bc9672319146765a2fba5270668d552b2bcd4924e9b660ad78347' 
  AND token = 'jOqT2L4LEimDU1ZfSXAb3SoboxLuUQ3cZrYTgVbtMI0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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