SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd198ce0545e4cf1c6e2e82ae2f76acee68461efafe5c8874302270cd869cb835' 
  AND token = 'fJFdgwUS4ZtDhUlkq2Z38HnRjgLHnlgKFIecWIeQAR0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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