SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '493f178af68fccc42a650a2f4b3d3f554595599419bb2b0d3500d8f9d575da1f' 
  AND token = 'd+hrIB02lBUmYPn1TFcJZSC9DyfPPt9TgeQf5fN+S8I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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