SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b431efc78438fbceeffd7daf6213cabba790899288c6c4fd8264eb45b9fc43b0' 
  AND token = 'qKYBDZG+CGRqQzYuqRBoPBeMVKfg60qaGi84NQM1Zm0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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