SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4b701354c1c8ecb432271c95818068833866363ec51d5d127565e78249d9826' 
  AND token = 'Hu9muJQgQvtQgP8KPoAjzt3z5fO3OEgb7xUCkQ/9yVk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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