SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c2bad3dfb3ac0fd1c09619940fe86d20723e10eebe4cdabcf2edbf1e9ce1030e' 
  AND token = '/I0ZiSFZyI1vLcrDw8zi4UeI8rtGmADO0fvCXP/7gqs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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