SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '286b24890a25c4b7b81d4d9bd2931ae9308a681dc24680fb58fa1c300fc6e814' 
  AND token = 'y32AJzrR73gJfoUa7c1F+ELuvJ+SElWp0l2RydLJGME=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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