SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec73aba652e993c860a704c13d2cb27f96fea9b5859d1759b99ea2eaddf2ec78' 
  AND token = 'Sg81jXAL34KJQNih59Ws94RWi3PKT1E8niOVQ39NDBE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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