SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '16a3733c571ec98dd5dddc77965c1f8f3d132866b76384a2d4a88143510bcb13' 
  AND token = 'ibLFSnztG+17BQNRetLdlzC4c9B+xGC+6DRgoLmB+Pw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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