SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55f9a2cb4a19a69025bad9cb07514dc84eff0b531c5074ec4efac79cdbeed975' 
  AND token = 'dXK6ngxU/uxa1ruXgTbXy8H3ieX2Lo2YEAmiYmCQxtw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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