SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '47df3eed4ea20c4b79cf2ccd86dd8c519d64e663503b8b9e08131c65b81ea020' 
  AND token = 'L7pe9ppow99UQsVRgOc/RDDGrcyjgjSflW+e6Tbjf5w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}