SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9f4df0fbd76ac1194e0c72b9103117295ec5092245b844b2bb5e6e687c7cd968' 
  AND token = 'Xemzptxddei/rpzrqHfGkgVDR89P7pdzheciUcQhkpo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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