SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '81833b7d69723469cc518874e801981f4eeb665d27f6de926ea6ddbf2a3a7e23' 
  AND token = 'Yv2smc018msHzHvfwKEztsXKJVp3N1lrDxPrlKfSyoM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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