SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6692fbe40843ee6c568df1de2233b10f431e2fc423a5590675a119ed81ff559' 
  AND token = '6cEItEIl/BlF4cJ+QINfa5N/H3RaFF3KsZVxXPV0fQ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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