SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '998f9444f5daae3fa9b7af622fa0d601113cf4d4aee382a8ea5d1a25be9ff009' 
  AND token = 'vysi+sCHmZlhDWC5A7jOGwzOpskTdPcLZ3T3NpfB0zw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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