SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83165df93bdc28f327f44ead3aa46000e6cd9ada3a5aa75bd2e140f7fcb26875' 
  AND token = 'AOUgahGtaTsRmXmr6ll8NYfmYuOAIKmBicZX/2db2is=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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