SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e830f786210db4a3572a51abdd7a522c0c1df1112c34419bccc4a5bfd5419876' 
  AND token = 'L6GmeOdUNmWTGckvwFRsAkaCVt+foVMVna8SeoIU7pY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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