SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b8dbcc04a57be9d7d2be98b6f9299fee92eaed6805adf362ed2d0c0f6454acb5' 
  AND token = 'GRc9fQGz8pHW0+oKiLcQKElHbIwSDYENDMu9yFqlsKc=' 
  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"
    }
  }
}