SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36aa6efe22f51ea6df838c237a024943692be4509fa0d1c86ee0700fef124c3c' 
  AND token = '+pAJVpybZzjVqPJcyeQlf93oQ2HAhDy6/ITyzmlVnWU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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