SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '574329252442e5d34d79e61ffe20fe8c23cf9b0fb2e741a72fdb30953c3766d0' 
  AND token = 'F50KxRMX1lpFg1pYWhGqT9PATgf6J/axPu+agPmLbZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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