SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb8b82ca4363dcfcb78aeab285204f747f318fbd23889d2f3296e76ee7ecce45' 
  AND token = 'aU756AelPPtImwzdcJGIxxwGDMWhJgwT03ef4cjpQoc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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